This November voters in three Bay Area counties will have the chance to vote on a $3.5 billion bond measure to pay for critical repairs and improvements for BART, including station improvements, new rails, and an improved train-control system that will allow trains to cross the bay more frequently at peak hours. Riders on BART log about 430,000 trips a day, so when BART breaks the Bay Area waits. Many of those riders turn to cars and bring traffic to a halt. We need to pass Measure RR to make BART reliable and safe.

For far too long, BART focused on costly expansion projects with limited ridership at the expense of basic maintenance of the core system. TransForm and other advocates have been pushing for years for BART to address existing problems and repairs before growing the system, and with Measure RR they’re finally doing exactly that — and not a moment too soon.

BART is at a crossroads right now. This measure would almost close the gap on the unfunded maintenance backlog that has plagued the system for years, enabling BART to meet growing demand with more frequent service, better facilities, and updated equipment. The train control system, much of the tracks, and other key infrastructure like the Transbay Tube are original to when the system opened 44 years ago. That equipment won’t last forever.

If we don’t pass Measure RR, it’s unclear how the necessary work will get done. BART is expensive enough, and fare increases seem likely to help fill the gap if Measure RR fails. Under-funding BART (or any transit system) is a vicious cycle – lack of cash leads to fare increases, service cuts, and sub-standard facilities, which discourage ridership and undermine public support for the system, making it ever-harder to dig out of the hole.

Measure RR can interrupt this downward spiral and put BART on a more sustainable path before major equipment failures turn a simmering problem into a regional crisis. This is the change we’ve been calling for, and we’re unlikely to get a second shot at it.

It wasn’t just a change of heart that led BART to this new approach, it was a change of leadership. New BART board directors elected by voters in the past several years, and a new general manager hired in 2011, have helped usher in this new era of more responsible stewardship of the system.

We trust these leaders to also be responsible stewards of taxpayer dollars in managing the repayment of this bond. The actual tax rates to repay the only other BART bond in recent years, an earthquake safety measure passed in 2004, have come in below BART’s original projections.

Whether you’re a frequent BART rider or not, if you live in the Bay Area you benefit from safe, reliable, frequent, and affordable BART service. BART keeps millions of cars off our already-congested roads every week. It gets hundreds of thousands of people to work and school every day with minimal air pollution and carbon emissions, and is key to our region’s climate protection goals.

So will we take advantage of this long-awaited and hard-won opportunity to interrupt the vicious cycle and put BART on track to carry the Bay Area into a low-carbon future? Or will we keep playing into it, punishing the system for its current short-comings and kicking the can down the road?

Ridership is expected to increase to 600,000 daily trips by 2040, and the system must begin preparing for that future today. Voters in San Francisco, Alameda, and Contra Costa counties can make it happen by voting yes on Measure RR on Nov. 8.

Joël Ramos is regional planning director at the advocacy group TransForm.